As the number of available landfill sites for waste disposal decreases the disposal of scrap tires is becoming an increasing environmental problem In the United States, for example, 240 million tires are discarded annually and in some states dumps of used tires cover many hectares of land. These dumps are unsightly, occupy land that could be put to other uses and provide cover for vermin Also, the fire risk associated with tire dumps is considerable, fires fueled by burning tires being very difficult, if not impossible, to extinguish. A further danger from burning tires is the noxious emissions of sulphur dioxide gas which result, due to the high sulphur content of tires. In addition, the soil beneath such fires becomes "poisoned" and will not support plant growth and may even have to be removed for safe disposal.
In recent years, recycled tires have been put to various uses including the production of domestic door mats and landing mats for aircraft, while others are ground up with asphalt to make rubber pavements. In more recent developments, tires are ground to a powder which is added to other plastics to form a composite useful to make a variety of products such as pipes, drains, fence posts and boards. However, demand for recycled tires has not yet reached a level capable of substantially depleting the stockpile of scrap tires now in existence.
Even if recycling of tires increases, the storage and transport of scrap tires is still inefficient as tires occupy a large volume relative to weight. It would therefore be advantageous to reduce the volume in some way. This can be achieved by splitting tires in half, such that the halves may sit inside one another. However, tire splitting has not presented a practical solution to the problem as operators have had to work with machinery which is inconvenient and often unsafe to use and far too slow to be economically viable.